Quick Guide To Large Polyp Caribbean Corals

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Large Polyps

When most people imagine corals, they think of hundreds of tiny polyps creating a larger colony of coral. And while this is true for most corals there is a second category of corals which have large polyps, and even single large polyp species.

Large polyp corals are anywhere between 5-15cm or 1-6 inches in diameter, and often the most colorful of all coral species. We made this quick guide so you can easily identify large polyp Caribbean species at a glance.

Mussa

Mussa is a colonial large polyp coral that has fleshy inflated polyps hiding an oblong shaped skeleton. The polyps are up to 15 or 6 inches in diameter and can be different shades of gray with hints of green, blue, red, orange or pink.

Because of the fleshy mantle, this coral could be mistaken for a Scolymia, which is a round single fleshy polyp. However, Scolymia corals always grow as a single polyp with a round skeleton. Mussa polyps are colonial and have kidney or oblong shaped skeleton.

Eusmilia

Eusmilia is a common coral found in the Caribbean, and with only one species (Eusmiliafastigiata) you should all quickly become experts in identifying this recognizable coral.

Eusmilia colonies can grow into small mounds about 20 in (50 cm) across. Polyps are a few cm or less than an inch in diameter. The colony grows long tubular corallites that extend from the base in groups of one, two or three. The tips of each polyp are oval or peanut shaped and have a ridged texture. Tentacles are visible at night.

Scolymia

There are two species of Scolymia the smaller solitary disk coral, (Scolymia cubensis), and the large fleshy disk coral (Scolymia lacera). Scolymia cubensis has a smooth fleshy mantle and a mouth in the center of the coral, while Scolymia lacera has pointed skeletal teeth around the edge of the coral.

At first glance, you might even think this is a soft coral because of the puffy ring surrounding the oral disk. But rest assured this is a species of stony coral and underneath the fleshy polyp is a hard calcium carbonate skeleton.

Scolymia corals are the crown jewel, and a big reason I still get excited about Caribbean diving. You can never predict the endless combinations of colors, patterns, or stripes. If there was ever a definition of a diamond in the rough, this is it. This polyp is between 3-8cm or 1-3 inches across.

If you’re like me, every time you get it the water, scuba diving comes with a wish list of corals (or fish) you want to see. In the Caribbean, my list always includes Scolymia lacera.

Mature colonies of Scolymia lacera can be up to 15cm or 6 inches and I’ve even found a few up to 20cm or 8 inches around. Scolymia can have stripes or splotches, with every color imaginable. And there will always be that chance to find that one extraordinary specimen which shines brighter than the rest. That is what makes searching for corals a never-ending treasure hunt.

This image compared the difference between two scolymia corals. Notice how the tissue hugs the skeleton, whereas the tissue from the Mussa extends around the coral like a skirt.

For easy quick access to this quick guide save the graphic below on your phone.

Nicole (Nikki) Helgason is a PADI Dive Instructor with ten years of professional dive experience. Nicole has taught scuba diving and managed dive centers around the world. Nicole has a Bachelors degree in Coastal Geography from the University of Victoria and is passionate about coral reefs.